Creates a new vertical scale widget that lets the user input a number
between min and max (including min and max) with the increment
step. step must be nonzero; it's the distance the slider moves when
using the arrow keys to adjust the scale value.

Note that the way in which the precision is derived works best if step
is a power of ten. If the resulting precision is not suitable for your
needs, use Graphics.UI.Gtk.Abstract.Scale.scaleSetDigits to correct it.